Casing for housing disc cartridge and method for packaging the casing

ABSTRACT

A casing for a disc cartridge includes first and second halves and a pair of holding means. The first half includes a plate portion, a pair of sidewall sections formed parallel to the parallel sides of the plate portion and a wall section between the sidewall sections. The second half includes a plate portion, a pair of sidewall sections formed parallel to the parallel sides of the plate portion and a wall section between the sidewall sections. Each of the sidewall sections is formed with a protrusion and a groove. The first and second halves are connected together by having the protrusion engaged in the groove. A holding unit is provided in an inner portion of the second half.

This is a continuation of application Ser. No. 08/036,626 filed on Mar.24, 1993 now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a disc cartridge casing for packaging a disccartridge comprised of a recording disc, such as an optical disc of amagneto-optical disc, contained in a main cartridge body. Moreparticularly, it relates to a sleeve casing for a disc cartridge and amethod for packaging the sleeve casing with the disc cartridge therein.

A so-called sleeve casing has been proposed as a casing for packagingthe disc cartridge comprised of the recording disc and the cartridgemain body housing the disc, or a tape cassette comprised of a tape reelfitted with a recording tape and a cassette housing the tape reeltherein.

The sleeve casing 401 is formed by a sheet-shaped member of a syntheticmaterial, such as polypropylene (PP) or polyethylene terephthalate(PFT), bent into a box one side of which is opened at 404 to provide apouch-shaped structure, as shown in FIG. 1. The above-mentionedcassette, having the recording medium housed therein, is introduced intoand held within the sleeve casing 401 via the opening 404. In general,the sleeve casing 401 is of a size just large enough to accommodate thecassette having the recording medium therein to hold the cassette by theforce of friction between the outer surface of the cassette and theinner surface of the sleeve casing. The sleeve casing 401 has cut-outs402,403 at forward ends of the major surfaces of the casing incontinuation to the opening 404 for ease in taking out the cassette fromthe sleeve casing.

Meanwhile, since the sleeve casing is formed by bending a sheet-shapedmember formed of paper or the synthetic resin, it can not be increasedin thickness beyond a certain limit in order to retain its foldability,thus rendering it difficult to develop a sufficient toughness.

If the sleeve casing is used as a casing for holding a disc cartridge,the following problem arises. That is, if the casing for holding thedisc cartridge therein is not of a sufficient toughness, the disccartridge cannot be protected reliably. That is, if an external pressureis applied to the casing with the disc cartridge contained therein, thecasing tends to be deformed easily. The result is the possibledestruction or deformation of the disc cartridge contained in the casingunder an external pressure. On the other hand, if plural disc cartridgescontained in the respective casings be stacked one upon the other, thecasings tend to be deformed under the weight of the overlying disccartridges. The result is again the possible destruction or deformationof the disc cartridges.

Besides, the conventional sleeve casing for the disc cartridge are notprovided with means for retaining the disc cartridge contained therein.Consequently, the disc cartridge tends to be disengaged out of thecasing under shock or vibrations. If the disc cartridge be disengagedout of the casing while it is transported while being contained therein,there is a risk that the disc cartridge will fall on the floor or groundand be destroyed under the resulting shock.

Besides, since the disc cartridge is formed by bending a sheet-shapedmaterial, the opening via which the cartridge main body is introducedinto or taken out of the casing cannot be formed with ease to apredetermined shape in the casing. Besides, since the opening in thecasing tends to be deformed, difficulties tend to be incurred in theoperation of introducing the disc cartridge into the casing.

As a solution to such problem, it may be contemplated to form the casingof two casing halves, that is a top plate member and a bottom platemember, similar to two halves of the cartridge main body, these twoplate members being abutted and connected to each other to complete acasing. In such case, these members are cast integrally by injectionmolding without the necessity of performing a bending or foldingoperation. The result is that these plate members can not be formed of asufficiently tough material.

However, if the two plate members of the casing be connected together byset screws, the two plate members become complicated in structure.Besides, since female screws need to be provided so as to clear the disccartridge, the top and bottom plate members become bulky in size ascompared to the disc cartridge.

If the top and bottom plate members are connected together by so-calledultrasonic welding, the surface region of the plate members tend to bedamaged by propagation of ultrasonic waves to detract from theappearance of the casing which should be as neat as possible. On theother hand, ultrasonic welding tends to scrape fused ribs formed alongthe junction line of the top and bottom plate members to produce debriswhich then tends to be left within the casing to be intruded later intothe inside of the disc cartridge so as to be deposited on the discwithin the disc cartridge to render it impossible to record and/orreproduce signals satisfactorily. Besides, the top and bottom platemembers thus connected together by ultrasonic welding tend to bedetached from each other due to insufficient durability under hightemperature high humidity conditions.

If the top and bottom plate members are connected together using anadhesive, it takes some time until curing of the adhesive so that promptconnection cannot be achieved. Besides, it becomes necessary to controlthe amount of application of the adhesive so that an excess amount ofthe adhesive is not extruded from the space between the two platemembers, thus leading to a complicated operation. In addition, atroublesome adhesive control operation is required to prevent the unusedadhesive from being cured or to prevent the adhesive power from beinglowered. The two plate members thus connected together by the adhesivetend to be detached from each other due to insufficient durability underhigh temperature high humidity conditions.

There may be occasions wherein the sleeve casing 401, shown in FIGS. 1to 3, ready to be sold with a disc cartridge contained therein, is to bepackaged with a film member of synthetic resin, such as an overlap film.This packaging is performed by so-called caramel wrapping, in which asleeve casing 401 is introduced into the inside of an overlap film whichis connected at opposite sides. Both end faces of the overlap film arefolded inwards to form superposed portions which are heat-weldedtogether to complete the wrapping. The heat welding is carried out byapplying a heated ironing member, such as a heated metal plate, on thesuperposed portions of the overlap film. The overlap film issubsequently heat shrunk so as to be tightly affixed to the outersurface of the sleeve casing 401.

Meanwhile, since the overlap film is ultimately heat shrunk into tightcontact with the outer surface of the sleeve casing 401, if anyirregularities are present on the surface of the overlap film, theoverlap film tends to be creased around these irregularities.

These creases not only detract from the appearance of the casing butalso tend to catch the finger of a person handling the casing to producerupture or severance of the heat-welded portions.

Since the above-mentioned cut-outs 402, 403 are formed in the sleevecasing 401, the outer lateral surface of the casing presents a step whenthe cassette, such as a disc cartridge is accommodated in the casing, asshown in FIGS. 2 and 3. That is, the major surfaces of the sleeve casing401 present steps corresponding to the thickness of the casing asindicated by arrow d in FIG. 2. Besides, on the front side of thecasing, there are formed ribs on both lateral sides of the cut-outs 402,403 corresponding to the amount of projection of the major surfaces ofthe sleeve as indicated by arrow S in FIG. 3.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a casingfor a disc cartridge which resolves the above-mentioned problems.

It is another object of the present invention to provide a casing for adisc cartridge exhibiting sufficient toughness.

It is a further object of the present invention to provide a packagingmethod for the casing for the disc cartridge whereby creasing is notincurred in the wrapping material.

According to the present invention, there is provided a casing havingfirst and second halves and a pair of holding members. The first, halfincludes a plate portion, a pair of sidewall members formed along theparallel sides of the plate portion, and a wail member provided betweenthe sidewall members. Each of the side wall members is provided with aprotrusion and a groove, and the first and second halves are connectedtogether by engagement of the grooves and the protrusions of the firstand the second halves. The holding members are provided in the innerportion of the second half.

According to the present invention, there is also provided a packagingmethod for a casing having an opening and a cut-out formed from theopening in the side of the casing, comprising the steps of applying asheet-shaped member covering at least said opening and said cut-out,applying a film in a tubular form so that superposed portions are formedon the lateral sides of the casing, and heating said superposed portionsfor fusing the ends of said film.

The basic arrangement of the casing of the present invention consists ofconnecting the first and second halves by engagement of the grooves andprotrusions formed on the three sidewall sections and in opening theremaining sidewall when the first and second halves are connectedtogether. The result is that the casing may be constructed of a materialexhibiting sufficient toughness as in the casing for the disc cartridge.

By applying a sheet-shaped material to cover up the opening side and thecut-outs of the casing before covering the casing with an overlap film,the casing to be packaged presents a planar outer surface in itsentirety. Creases may then be prevented from being produced in the filmafter completion of packaging.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the shape of a conventional sleevecasing.

FIG. 2 is an enlarged partial perspective view showing irregularities onthe outer lateral surface of the conventional sleeve casing shown inFIG. 1.

FIG. 3 is an enlarged partial plan view showing irregularities on theouter lateral surface of the conventional sleeve casing shown in FIG. 1.

FIG. 4 is a perspective view showing a casing for a disc cartridgeaccording to the present invention and a disc cartridge about to beintroduced therein.

FIG. 5 is a perspective view, as seen from the bottom, showing anarrangement of the disc cartridge shown in FIG. 4.

FIG. 6 is a front view showing the arrangement of the casing shown inFIG. 4.

FIG. 7 is a back view showing the arrangement of the casing shown inFIG. 4.

FIG. 8 is a bottom view showing the arrangement of the casing shown inFIG. 4.

FIG. 9 is a front view showing the arrangement of the casing shown inFIG. 4.

FIG. 10 is an exploded perspective view showing the arrangement of thecasing shown in FIG. 4.

FIG. 11 is a perspective view, as seen from the bottom side, showing anarrangement of a top plate member constituting the casing for the disccartridge shown in FIG. 4.

FIG. 12 is a side view showing an arrangement of a top plate member.

FIG. 13 is a side view showing an arrangement of a top plate memberconstituting the casing for the disc cartridge.

FIG. 14 is a front view showing the shape of a top plate memberconstituting the casing for the disc cartridge shown in FIG. 4.

FIG. 15 is a bottom view showing the shape of a top plate member.

FIG. 16 is a plan view showing the shape of a bottom plate memberconstituting the casing for the disc cartridge shown in FIG. 4.

FIG. 17 is a front view showing the shape of the bottom plate member.

FIG. 18 is an enlarged partial perspective view of the bottom platemember shown in FIG. 17.

FIG. 19 is an enlarged partial perspective view showing a modificationof the bottom plate member.

FIG. 20 is an enlarged partial cross-sectional view showing the state ofengagement of the top and bottom plate members at the lateral sides inthe casing for the disc cartridge.

FIG. 21 is an enlarged partial cross-sectional view showing the state ofengagement of the top and bottom plate members at the rear sides in thecasing for the disc cartridge.

FIG. 22 is a perspective view showing another modification of the bottomplate member constituting the casing for the disc cartridge.

FIG. 23 is a perspective view, as seen from the front side, showing theshape of the locking member constituting the casing for the disccartridge.

FIG. 24 is a perspective view, as seen from the rear side, showing theshape of the locking member.

FIG. 25 is a plan view showing the shape of the locking member shown inFIG. 24.

FIG. 26 is a plan view showing the shape of a bottom plate memberconstituting the casing for the disc cartridge.

FIG. 27 is a perspective view showing the state of a first manner ofmistaken insertion in the casing for the disc cartridge.

FIG. 28 is a perspective view showing the state of a second manner ofmistaken insertion in the casing for the disc cartridge.

FIG. 29 is a perspective view showing the state of a third manner ofmistaken insertion in the casing for the disc cartridge.

FIG. 30 is a transverse sectional view showing the state in which thedisc cartridge is contained and held in the casing for the disccartridge.

FIG. 31 is a longitudinal sectional view showing the state in which thedisc cartridge is contained and held in the casing for the disccartridge.

FIG. 32 is a longitudinal sectional view showing the state in which thedisc cartridge is inserted in a mistaken manner into the casing and suchmistaken insertion is inhibited.

FIG. 33 is a transverse sectional view showing the disc cartridgeinserted in a mistaken manner into the casing for the disc cartridge.

FIG. 34 is a longitudinal sectional view showing the state in which thecasing for the disc cartridge has been packaged with an overlap film.

FIG. 35 is a longitudinal sectional view showing a state in which theoverlap film is shifted to one side from the state of FIG. 34 when thecasing for the disc cartridge is wrapped with the overlap film.

FIG. 36 is a longitudinal sectional view showing the state in which theoverlap film is shifted to the opposite side from the state of FIG. 35when the casing for the disc cartridge is wrapped with the overlap film.

FIG. 37 is a transverse sectional view showing another state ofpackaging of the casing with an overlap film.

FIG. 38 is a longitudinal sectional view showing a state in which theoverlap film is shifted to one side from the state of FIG. 37 when thecasing for the disc cartridge is wrapped with the overlap film.

FIG. 39 is a longitudinal sectional view showing the state in which theoverlap film is shifted to the opposite side from the state of FIG. 38when the casing for the disc cartridge is wrapped with the overlap film.

FIG. 40 is a perspective view showing the state in which a label memberis about to be applied to the casing when packaging the casing with anoverlap film.

FIG. 41 is a perspective view showing the state in which a casing for adisc cartridge is packaged with an overlap film.

FIG. 42 is a perspective view showing a modified shape of the labelmember.

FIG. 43 is an enlarged partial perspective view showing the state inwhich the locking member of the casing for the disc cartridge accordingto a first modification of the present invention is held by the bottomplate member.

FIG. 44 is an enlarged partial perspective view showing anothermodification of the locking member and the manner in which the lockingmember is held by the bottom plate member.

FIG. 45 is an enlarged partial plan view showing the state in which thelocking member is held by the bottom plate member.

FIG. 46 is an enlarged partial plan view showing the state in which thebent arm of the locking member is flexed resiliently.

FIG. 47 is an enlarged partial perspective view showing anothermodification of a locking member constituting a casing for a disccartridge according to the present invention.

FIG. 48 is an enlarged partial plan view showing an arrangement of thelocking member shown in FIG. 47.

FIG. 49 is an enlarged perspective view showing the shape of essentialpart of the bottom plate member of the casing for the disc cartridgeaccording of a fourth modification.

FIG. 50 is a perspective view showing the shape of the bottom platemember shown in FIG. 49.

FIG. 51 is a longitudinal sectional view showing the state in which adisc cartridge is being inserted into the casing.

FIG. 52 is a longitudinal sectional view showing the state in which adisc cartridge has been inserted into the casing.

FIG. 53 is a side view showing the arrangement of a top plate member ina modification of the casing according to the present invention.

FIG. 54 is a side view showing the arrangement of a bottom plate memberin another modification of the casing according to the presentinvention.

FIG. 55 is an enlarged partial cross-sectional view showing the engagedstate at the rear side between the top plate member and the bottom platemember shown in FIGS. 53 and 54.

FIG. 56 is an exploded perspective view showing a disc cartridgeconstituted by the top plate member and the bottom plate member shown inFIGS. 53 and 54.

FIG. 57 is an enlarged perspective view showing the shape of essentialparts of the bottom plate member shown in FIG. 54.

FIG. 58 is an enlarged perspective view showing a modification of theshape of essential parts of the bottom plate member shown in FIG. 54.

FIG. 59 is a longitudinal sectional view showing the manner in which thedisc cartridge is being inserted into the casing shown in FIG. 56.

FIG. 60 is a longitudinal sectional view showing the manner in which thedisc cartridge has been inserted into the casing shown in FIG. 56.

FIG. 61 is an enlarged partial perspective view showing essential partof the top plate member of the casing according to a fifth modification.

FIG. 62 is an enlarged partial perspective view showing essential partof the bottom plate member.

FIG. 63 is an enlarged partial longitudinal sectional view showing anarrangement of a bottomed hole of the casing for the disc cartridge.

FIG. 64 is an enlarged partial longitudinal sectional view showingessential part of the top plate member of the casing according to afifth modification.

FIG. 65 is an enlarged partial longitudinal sectional view showingessential part of the top plate member of the casing according to afurther modification.

FIG. 66 is an enlarged partial longitudinal sectional view showingessential part of the top plate member of the casing according to astill further modification.

FIG. 67 is an enlarged cross-sectional view showing essential part of ametal mold for molding the top plate member and the bottom plate member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, certain preferred embodiments of the presentinvention will be explained in detail.

FIG. 4 shows a casing 100 for a disc cartridge 101 according to thepresent invention. This disc cartridge 101 includes a cartridge mainbody 102 and a recording disc, such as an optical disc or amagneto-optical disc, accommodated therein.

The disc cartridge 101 includes the cartridge main body 102 made up ofupper and lower halves 103, 104 abutted and connected to each other inthe form of a thin case, as shown in FIGS. 4 and 5. The recording disc117 is housed for rotation within the cartridge main body 102.

The recording disc 117 includes a disc substrate formed of a syntheticresin and a signal recording layer deposited on one of the majorsurfaces of the disc substrate. The recording disc 117 has a centerchucking aperture 114. The rim part of the chucking aperture 114 on themajor surface of the disc substrate serves as a chucking referencesurface 116. A chucking plate 115 is mounted on the opposite majorsurface of the disc substrate for closing the chucking aperture 114.

The cartridge main body 102 is formed as a thin case having asubstantially rectangular major surface having a side having a lengthsubstantially corresponding to the diameter of the recording disc 117. Apair of substantially rectangular recording/reproducing apertures 106,107 are formed in register with each other on the upper and lower majorsurfaces of the cartridge main body 102. The recording/reproducingaperture 107 in the lower half 104 causes one of the major surfaces ofthe recording disc 117 to be exposed to outside across the inner andouter rims of the disc 117. The recording/reproducing aperture 106 inthe upper half 103 causes the other major surface of the recording disc117 to be exposed to outside across the inner and outer rims of the disc117.

The recording/reproducing apertures 106, 107 are opened or closed by ashutter member 105 slidably mounted on the cartridge main body 102. Theshutter member 105 is formed from a thin metal sheet by bending it intoa substantially U-shape and includes a pair of shutter plates foropening and closing the recording/reproducing apertures 106, 107. Theshutter plates are interconnected at a center web portion and extendedparallel to each other. The shutter member 105 has its center webportion slidably supported by a lateral side of the cartridge main body102 so that the shutter plates are extended parallel to the majorsurfaces of the cartridge main body 102. When the shutter member 105 ismoved to a position in which the shutter plates are in register with therecording/reproducing apertures 106, 107, the shutter plates close theserecording/reproducing apertures 106, 107. As shown by arrow B in FIGS. 4and 5, the shutter member 105 is slid rearwards with respect to thedirection of introducing the disc cartridge 101 into therecording/reproducing apparatus indicated by arrow A in FIG. 4. Theresult is that the shutter member 105 has its shutter plates movedtowards rear on the major surface of the cartridge main body 102 to openthe recording/reproducing apertures 106, 107.

A circular chucking aperture 108 is formed at a center position on thelower major surface of the cartridge main body 102. The chuckingaperture 108 causes the chucking aperture 114, chucking referencesurface 116, and the chucking plate 115 of the recording disc 117 to beexposed to the outside.

The lower major surface of the cartridge main body 102 has a pair ofpositioning holes 112, 113 for positioning the disc cartridge when thedisc cartridge is loaded in position on the recording/reproducingapparatus. These positioning holes 112, 113 are formed in the vicinityof the front and rear ends in the lower major surfaces of the cartridgemain body 102.

The lower major surface of the cartridge main body 102 is formed with apair of recesses 110, 109 and a disc type discriminating recess 111. Therecesses 110, 109 are adapted for capturing the disc cartridge by thedisc loading unit of the recording/reproducing apparatus. These recesses110, 109 are formed on both lateral sides at the front side of the lowermajor surface of the cartridge main body 102 so as to be opened on thelateral sides of the cartridge main body 102. The disc typediscriminating recess 111 is formed on the front side in the lower majorsurface of the cartridge main body 102. The disc type discriminatingrecess 111 has its depth set depending on the type of the recording disc117 housed in the cartridge main body.

The casing for the disc cartridge according to the present invention ismade up of a top plate member 1 as a first member and a bottom platemember 2 as a second member, as shown in FIGS. 4 and 6 to 10.

The top plate member 1 has a top plate section 1a of a size and shapesubstantially corresponding to the size and shape of the major surfaceof the cartridge main body 102, and is integrally cast from e.g. asynthetic resin in the form of a flat plate. The top plate member 1 isformed of a light-transmitting material, such as acrylic resin, e.g.polymethacrylate, ABS resin, polycarbonate or polystyrene.

The top plate member 1 has a pair of inner sidewall members 11, 12 onboth lateral sides of the lower surface thereof extending parallel tothe lateral sides of the top plate section 1a, as shown in FIG. 11. Thetop plate member 1 also has an inner rear wall member 15 parallel to therear side of the top plate section 1a, as shown in FIG. 11. The innersidewall members 11, 12 and the inner rear wall member 15 are cast asone with the top plate section 1a for defining a U-shaped peripheralwall interrupted at the front side. These sidewall sections 11, 12 andthe rear wall section 15 are of a height substantially equal to thethickness of the cartridge main body 102, and are inwardly offset fromthe lateral sides and the rear side of the top plate section la by adistance corresponding to the thickness of the wall sections 11, 12 and15.

On the outer lateral sides of the inner sidewall sections 11, 12 areformed lateral engaging ribs 13, 14 for extending laterally outwards, asshown in FIGS. 11, 12, 14 and 15. These engaging ribs 13, 14 areprovided for extending from the vicinity of the front side towards therear side and parallel to the lateral sides of the top plate section 1a.These engaging ribs 13, 14 are positioned slightly above the lower endsof the inner lateral sidewall sections 11, 12, that is towards the topplate section 1a.

On the outer lateral sides of the inner sidewall sections 11, 12 areformed retention projections 23, 24 for being extended rearwards. Theseretention projections 23, 24 are provided towards the front side of theinner sidewall sections 11, 12 adjacent to the upper surfaces of theengaging ribs 13, 14. These retention projections 23, 24 are protrudedby an amount slightly smaller than the amount of protrusion of theengaging ribs 13, 14. These retention projections 23, 24 are each of afront end face at right angles to the sidewall sections 11, 12 and arear end face inclined relative to the sidewall sections 11, 12 with theamount of protrusion being gradually decreased towards the rear side.

On the outer lateral sides of the inner sidewall sections 11, 12 areformed a pair of vertically extending slits 39, 40. These slits 39, 40are formed for being extended from the proximal ends towards the lowerends of the inner sidewall sections 11, 12.

On the lower surface of the top plate section 1a are formed a pair oflateral shoulders 48, 49 and a rear shoulder 50 on both lateral sidesand on the rear side, respectively. These shoulders 48 to 50 areprotruded only slightly to prevent the disc cartridge 101 introducedinto the casing 100 from being slidingly contacted with the mid portionof the top plate section 1a.

A cut-out 5 is formed on the front side of the top plate section 1a forcausing the rear end of the disc cartridge 101 housed within the casing100 to be exposed to outside.

The bottom plate member 2 has a bottom plate section 2b of substantiallythe same shape as the top plate section 1a and is cast as one fromplastics or like material. The bottom plate member 2 is formed of amaterial showing excellent heat resistance, such as heat-resistant ABSresin or polycarbonate.

The bottom plate member 2 has a pair of outer sidewall members 17, 18 onboth lateral sides of the upper surface thereof extending parallel tothe lateral sides of the bottom plate section 2a, as shown in FIG. 10.The bottom plate member 2 also has an outer rear wall member 19 parallelto the rear side of the bottom plate section 2a. The outer sidewallmembers 11, 12 and the outer rear wall member 15 are cast as one withthe bottom plate section 2a for defining a U-shaped peripheral wallinterrupted at the front side. These outer sidewall sections 17, 18 andthe rear wall section 19 are of a height substantially equal to thethickness of the cartridge main body 102, and are formed for extendingalong the lateral sides and the rear side of the bottom plate section2a.

In the inner lateral sides of the outer sidewall sections 17, 18 areformed engaging lateral grooves 20, 21 for extending inwards, as shownin FIGS. 13, 16 and 17. These grooves 20, 21 are formed parallel to theupper surface of the bottom plate section 2a from the vicinity of thefront sides towards the rear sides of the outer sidewall members 17, 18.These grooves 20, 21 are formed slightly above the proximal sides of theouter sidewall sections 17, 18, that is at slightly spaced apartpositions with respect to the bottom plate section 2a, with the upperends of the grooves 20, 21 serving as engaging lugs. On the inner sidesof the outer rear wall member 19, that is the front lateral side, of theouter rear wall member 19, a flange 22 operating as a rear engaging lugis formed for being protruded towards the front side. The flange 22 isprovided for being extended from one towards the other lateral sides ofthe outer rear wall member 19 along the upper edge of the outer rearwall member 19 in parallel with the upper surface of the bottom platesection 2a. The lower lateral side of the flange 22 and the bottom platesection 2a make up an engaging rear groove.

In the inner lateral sides of the outer sidewall sections 17, 18 areformed retention recesses 25, 26, respectively, for being openedinwards. These retention recesses 25, 26 are formed in register with theretention projections 23, 24 at forward sides of the outer sidewallmembers 17, 18 in communication with the upper sides of the engaginglateral grooves 20, 21. These retention recesses 25, 26 are eachslightly shallower in depth than the engaging lateral grooves 20, 21.

In the upper lateral edges of the outer lateral surfaces of the outersidewall members 17, 18 are formed recesses 37, 38 for extending assteps across the front and rear sides of the outer sidewall sections 17,18 along the upper lateral edges of the sidewall members 17, 18. Theupper sides of the recesses 37, 38 are opened towards the upper lateralsides of the outer sidewall members 17, 18.

The rear portions of the outer sidewall members 17, 18 are formed with apair of cut-outs 41, 42 in register with the vertical slits 39, 40.These cut-outs 41, 42 are formed for extending from the upper endstowards the proximal sides of the outer sidewall sections 17, 18.

The front side of the bottom plate section 2a is formed with a cut-out 6for causing a rear part of the disc cartridge 101 housed within thecasing 100 to be exposed to the outside.

On the lateral sides and the rear side of the bottom plate 2a are formeda pair of lateral steps 30, 31 and a rear step 32, respectively. Thesesteps 30 to 32, having a small amount of protrusion, are used forpreventing the disc cartridge 101 from being slidingly contacted withthe mid portion of the bottom plate section 2a when the disc cartridge101 is introduced into the casing 100.

The rear step 32 is formed with a mistaken insertion inhibitingprotrusion 29. This protrusion is formed at a position on the rear sideof the bottom plate section 2a slightly offset from the center towards alateral side of the bottom plate section 2a. The function of themistaken insertion inhibiting protrusion 29 will be explainedsubsequently.

On both end parts of the flange 22 are formed a pair of rib-shapedreinforcements 27, 28 in continuation to the flange 22, as shown inFIGS. 16 and 18. These reinforcements 27, 28 are cast as one with theinner surface of the outer rear wall member 19 for extending from theflange 22 up to the bottom plate section 2a. At the lower parts withinthe engaging lateral grooves 20, 21 are formed plural reinforcement ribs43 for extending from the lateral sides of the grooves 20, 21 up to thebottom plate section 2a.

Meanwhile, the reinforcements 27, 28, shown in FIG. 18, may be formed asshown at 28a in FIG. 19. The reinforcement 28a shown in FIG. 19 isformed on the entire surface of the flange 22 of the outer rear wallmember 19 and on both sides of the engaging rear groove.

The top plate member 1 and the bottom plate member 2 are provided withstep-shaped protrusions which are spaced apart from the sidewallmembers, as shown in FIG. 22. These protrusions 69, 68 are formed asribs as one with the upper surface of the bottom plate member 2 inparallel with the outer sidewall sections 17, 18.

The top plate member 1 and the bottom plate member 2 are connected toeach other by having the lateral engaging ribs 13, 14 engaged in theengaging lateral grooves 20, 21, as best shown in FIGS. 14-21, and byhaving the rear engaging rib 16 engaged between the flange 22 and thebottom plate section 2a, that is in the engaging rear groove. Forconnecting the top plate member 1 and the bottom plate member 2 in thismanner, the top plate member 1 is positioned ahead of the bottom platemember 2 and the rear sides of the lateral engaging ribs 13, 14 areintroduced at the front ends of the engaging lateral grooves 20, 21,with the top plate member 1 being then moved towards the rear forsliding the lateral engaging ribs 13, 14 within the engaging lateralgrooves 20, 21. When the top plate member 1 is slid until the top platesection 1a is in register with the bottom plate section 2a, the rearengaging rib 16 is engaged in the rear engaging groove, while theretention projections 23, 24 are engaged with the retention recesses 25,26. For engaging the retention projections 23, 24 in the retentiongrooves 25, 26, these retention projections 23, 24 are first introducedinto a space between the sidewall members 17, 18, from the front ends ofthe outer sidewall members 17, 18 for outwardly thrusting and therebyslightly deflecting the outer sidewall members 17, 18. As the retentionprojections 23, 24 reach the position facing the retention recesses, theouter sidewall members 17, 18 are restored to their initial states forengaging the retention projections 23, 24 in the retention recesses 25,26.

The top plate member 1 and the bottom plate member 2 are engaged witheach other at the lateral sides and rear sides of the top plate section1a and the bottom plate section 2a, with the top plate section 1a andthe bottom plate section 2a extending parallel to each other, fordefining an opening at the front side. This opening has a lengthsubstantially corresponding to the length of a side of the cartridgemain body 103, and a width substantially corresponding to the thicknessof the cartridge main body 102. The lower ends of the inner sidewallmembers 11, 12 and the inner rear wall member 15 are caused to bearagainst the upper surface of the bottom plate section 2a, while theupper ends of the outer sidewall members 17, 18 and the outer rear wallmember 19 are caused to bear against the rim of the lower surface of thetop plate section 1a.

The recesses 37, 38 formed on the upper sides of the outer sidewallmembers 17, 18 and both lateral sides of the top plate section 1adelimit lateral grooves 7, 8. That is, the upper ends of the outersidewall members 17, 18 are engaged with the lateral sides of the topplate section 1a at the positions offset inwards by a distance equal tothe depths of the recesses 37, 38, as shown in FIG. 20. These lateralgrooves 7, 8 are formed for being extended from the front side towardsthe rear side of the lateral surface of the casing 100. The rear bottomends of the lateral grooves 7, 8 are formed with bottomed holesconstituted by slits 41, 42 formed in the outer sidewall members 17, 18and by the vertical grooves 39, 40 formed in the inner sidewall members11, 12.

Meanwhile, an injection gate of a metal mold for injection molding thetop plate member 1 is formed as a so-called pin gate at a positionsightly offset towards the rear on the upper surface of the top platesection 1a, as shown at G₁ in FIG. 15. An injection gate of a metal moldfor injection molding the bottom plate member 2 is formed as a so-calledpin gate at a position sightly offset towards the rear on the lowersurface of the bottom plate section 2a, as shown at G₂ in FIG. 16. Thatis, the top plate member 1 and the bottom plate member 2 are similar toeach other in shape and the gate positions are in register with eachother. Consequently, the top plate member 1 and the bottom plate member2 are substantially similar in the state of deformation, such asshrinkage, caused by the cooling step during injection molding, so thatthe engaging ribs of the sidewall sections may be engaged smoothly witheach other. The injection gate may also be so-called film gates orsubmarine gates, instead of the pin gates. In these cases, the injectiongates on the top plate member 1 and on the bottom plate member 2 may bepositioned in register with each other to provide for a substantiallyequal state of deformation, such as shrinkage, to assure smoothengagement of the top and bottom plate members 1 and 2.

At a recessed position within the space between the members 1 and 2, apair of locking members 9, 10 are provided for retaining the disccartridge 101 introduced between these members 1 and 2. These lockingmembers 9, 10, formed of a flexible and resilient material, such aspolyacetal, are composed of end grips 44, 45 and a resilient arm 46spanning the end grips 44, 45, as shown in FIGS. 23 to 26. The end grips44, 45 are columnar-shaped and have their axes parallel to each other.The resilient arm 46 is arcuate in shape and interconnect the end grips44, 45. The resilient arm 46 is bent in a direction at right angles tothe axes of the grips 44, 45. The apex point of the arcuately bent arm46 is at an equidistant position with respect to the grips 44, 45. Thearcuately bent parts of the locking members 9, 10 play the part ofretention surfaces 47 for retaining the disc cartridge 101.

The locking members 9, 10 are mounted by a pair of locking membermounting sections 33, 34 formed on the bottom plate member 2. Theselocking member mounting sections 33, 34 are formed on the inner lateralsurfaces of the outer sidewall sections 17, 18 at the recessed innerends of the sidewall members 17, 18, as shown in FIG. 16. These lockingmember mounting sections 33, 34 are each provided with fore and aftholding protrusions 54, 55. These holding protrusions 54, 55 are formedat the lower parts of the outer sidewall members 17, 18 for beingprotruded inwards in continuation to the bottom wall section 2a. Thatis, these holding projections 54, 55 are provided at the corners betweenthe outer sidewall sections 17, 18 and the bottom plate section 2a.These holding protrusions 54, 55 are mounted facing each other at adistance substantially corresponding to the lengths of the lockingmembers 9, 10. The facing sides of the holding protrusions 54, 55 areformed with holding recesses 52, 53, respectively. These holdingrecesses 52, 53 are opened towards the top and are each of across-sectional profile of a part of an ellipse or an oblong circlehaving its longer axis oriented in the fore-and-aft direction. Thelocking members 9, 10 are held by the holding projections 54, 55 byhaving the grips 44, 45 fitted into the holding recesses 52, 53.

These locking members 9, 10 are mounted with the axes of the grips 44,45 at right angles to the bottom plate section 2a and with the retentionsurfaces 47 directed towards the inner side of the bottom plate section2a. That is, the arcuately bent arms 46 of the locking members 9, 10 areadapted for being protruded towards the inner side of the bottom platesection 2a. The arcuately bent arms 46 of these locking members 9, 10may be resiliently bent in a direction of approaching the outer sidewallmembers 17, 18. When the arms 46 are resiliently deflected in thismanner, the grips 44, 45 are moved in the fore-and-aft direction withinthe holding recesses 52, 53, respectively.

Meanwhile, the inner sidewall sections 11 , 12 of the top plate member 1are cut out at the rear parts so that the rear parts are shorter in adistance from the top plate section 1a than the central and forwardparts by a length corresponding to the width of the locking members 9and 10. This prevents the inner sidewall sections 11, 12 from beingabutted against the locking members 9, 10 held by the locking membermounting sections 33, 34, while preventing the locking members 9, 10from being detached upwards from the locking member mounting sections33, 34.

It is noted that the back sides of the locking member mounting sections33, 34, that is the rear parts of the outer lateral sides of the outersidewall members 17, 18, are subject to so-called sink during integralinjection molding of the bottom plate member 2. Such sink is producedbecause the portions of the outer sidewall members 17, 18 provided withthe locking member mounting sections 33, 34 are increased in thicknessas compared to other parts of the outer sidewall members 17, 18 andhence are receded inwards in the course of cooling during the moldingprocess. For preventing such sink from being produced, the portions ofthe outer sidewall members 17, 18 in register with the locking membermounting sections 33, 34 are hollow due to the provision of clearances35, 36.

For housing and holding the disc cartridge 101 in the above-describedcasing 100 for a disc cartridge according to the present invention, thedisc cartridge 101 is introduced into the space between the top platemember 1a and the bottom plate member 2a from the front side via theopening in a direction shown by arrow A in FIG. 4.

As the front side of the disc cartridge 101 reaches the rear side of thecasing 101, the lateral surfaces of the front side of the cartridge mainbody 102 thrust the retention surfaces 47, 47 of the locking members 9,10 for deflecting the arms 46, 46 in a direction of approaching theouter sidewall members 17, 18. When the front side of the cartridge mainbody 102 reaches a predetermined position of being substantially abuttedon the inner lateral wall 15 of the casing 100, the locking members 9,10 are in register with the recesses 110, 109. At this time, the arms46, 46 of the locking members 9, 10 are restored to their initial statesunder their own resiliency for causing the retention surfaces 47, 47 tobe engaged in the recesses 110, 109. With the retention surfaces 47, 47of the locking members 9, 10 engaging in the recesses 110, 109, the disccartridge 101 is retained and limited in its movement of being detachedrearwards, that is out of the casing 100 via the opening under shock orvibrations.

The mistaken insertion inhibiting protrusion 29 is fitted at this timein the disc discriminating recess 111 of the disc cartridge 101, asshown in FIG. 31.

The disc cartridge 101, which is now in position within the casing 100,is accommodated between and protected from outside by the members 1 and2.

When a plurality of casings 100 are inserted into a rack adapted forcontaining plural casings, they are held in position by the lateralgrooves 7, 8. The casings 100 may be protected against accidentalremoval from the rack by engaging means provided on the rack beingengaged in the bottomed openings formed by the slits 41, 42.

When the disc cartridge 101 housed within the casing 100 is to be takenout of the casing 100, the rear part of the disc cartridge 101 exposedto outside via the cut-outs 5, 6 is held by the finger and pulledrearwards with respect to the casing 100. This causes the retentionsurfaces 47, 47 of the locking members 9, 10 to be thrust by the forwardlateral sides of the cartridge main body 102, while causing the arms 46,46 of the locking members 9, 10 to be deflected in a direction ofapproaching the outer sidewall members 17, 18 for releasing theretention of the disc cartridge 101. The disc cartridge 101 may now betaken out of the casing 100 via the opening. As the disc cartridge 101is moved further rearwards, the locking members 9, 10 are reset to theirinitial states. The disc cartridge 101 may be moved further rearwards soas to be taken out of the casing 100.

The mechanism of preventing mistaken insertion of the disc cartridgeinto the casing of the present invention is explained.

The casing 100 of the present invention is designed to prevent the disccartridge 101 from being introduced up to the housing complete positionwithin the casing 100 even when the disc cartridge 101 is inserted viathe opening in the mistaken direction.

There are three possible cases of mistaken insertion of the disccartridge 101, namely the case in which the disc cartridge 101 isinserted with its lower major surface facing upwards and with the frontend side first, from the direction shown by arrow D in FIG. 27, the casein which the disc cartridge 101 is inserted with its lower major surfacefacing upwards and with the rear end side first, from the directionshown by arrow E in FIG. 28, and the case in which the disc cartridge101 is inserted with its upper major surface facing upwards and with therear end side first, from the direction shown by arrow F in FIG. 29.

In any of these cases, when the disc cartridge 101 is introduced intothe casing 100, the locking members 9, 10 are not aced by the recesses110, 109, so that the locking members 9, 10 remain thrust andresiliently deflected by the cartridge main body 102, as shown in FIG.33. If the locking members 9, 10 are left for extended period of time inthe resiliently deflected state, the locking members 9, 10 undergoplastic deformation so that the disc cartridge 101 inserted in theregular position cannot be held by the locking members 9, 10.

With the present casing 100, if the disc cartridge 101 is inserted in amistaken manner as described above, the mistaken insertion inhibitingprotrusion 29 is caused to bear against the cartridge main body 102 toinhibit the insertion thereof into the casing 100, as shown in FIG. 32.That is, the distance from the upper end face of the mistaken insertioninhibiting protrusion 29 up to the lower surface of the top platesection 1a, as indicated by arrow L in FIG. 32, is shorter than thethickness of the cartridge main body 102 as indicated by arrow T in FIG.2. Consequently, the disc type discriminating recess 111 is not faced bythe mistaken insertion inhibiting protrusion 29. If the protrusion 29 isnot engaged with the recess 111, the protrusion 29 is caused to bearagainst the cartridge main body 102 to inhibit insertion of the disccartridge 101 into the casing 100. Meanwhile, the protrusion 29 has aheight lower than the depth of the disc type discriminating recess 111.

The casing 100 which has accommodated the disc cartridge 101 therein asdescribed above is packaged with an overlap film 201 by a packagingmethod as shown in FIGS. 34 to 41. The overlap film 201 is a thermallycontractible film which is contracted on being heated and which ismelted on being heated further.

For packaging, a label member of paper 204, which is to be asheet-shaped member, is applied over the front end of the casing 100 soas to cover up the cut-outs 5 and 6. The label member 203 is bent at itsmid part into U-shape and applied to the casing 100 to cover up the topplate section 1a and the bottom plate section 2a of the casing 100. Thetwo parallel bent portions of the label member 204 are located atsubstantially the mid positions of the label member 204 and are spacedapart from each other by a distance corresponding to the thickness ofthe casing 100. With the label member 204 applied over the casing 100,the latter presents planar outer lateral surfaces.

Meanwhile, the label member 204 is used as a so-called index label. Thelabel member 204, used as index label, is made up of a label coated withan adhesive and a release paper to which the label is bonded.

The wrapping is what is termed a caramel wrapping. First, the casing 100is introduced into the inside of an overlap film 201 obtained byinterconnecting two opposing edges of two film halves. Both end parts ofthe overlap film 201 in the tubular form are bent inwards to formsuperposed sections 202, 203, as shown in FIG. 34. These superposedsections 202, 203 are heated and fused together by heat welding by apair of heating ironing members 301, 302 making up a wrapping unit.These superposed sections 202,203 are formed on the outer lateralsurfaces of the casing 100.

The heating ironing members 301, 302 are formed of metal and mounted inopposition to each other. These ironing members 301, 302 are heated to apredetermined temperature and moved relative to each other to change thedistance therebetween. These ironing members 301, 302 are provided withrecesses 303, 304 in the opposite lateral sides, respectively. Theserecesses 303, 304 are contoured to conform to the profile of the lateralsurfaces of the casing 100 so that both lateral sides of the casing 100may be introduced up to the bottom of the recesses. Since the ridges ofthe lateral surfaces of the casing 100 are rounded, both corners of therecesses 303, 304 are also rounded to present a cylindrical shape.

The recesses 303, 304 are profiled to permit the ridges of the casing100 to be inserted therein. The results is that, if the overlap film 201is shifted in one or the other direction so that the overlap film 201has its one end extending over the entire lateral surface of the casing100 to reach the opposite side, that is the top plate section 1a or thebottom plate section 2a, the extended portion of the overlap film maystill be heated by the ironing members 301, 302 so as to be heat welded,as shown in FIGS. 38 and 39.

The overlap film 201 is heated and shrunk so as to be tightly applied tothe outer surface of the casing 100 to complete the wrapping, as shownin FIG. 41. Since the casing 100 presents a planar outer surface, theoverlap film 201 may be tightly applied to the outer lateral surface ofthe casing 100 on which the label member 204 is applied previously.

Meanwhile, the superposed portions 202, 203 of the overlap film 201 areapplied to cover up the lateral grooves 7, 8, as shown in FIG. 34. Theportions of the superposed parts 202, 203 lying over the lateral grooves7, 8 are not thrust fully by the ironing members 301, 302 so that thereis a risk that these portions be not fused together.

It may be an occurrence that the overlap film 201 be partiallypositioned towards one or the other sides of the casing 100, as shown inFIGS. 35 and 36. In these cases, one of the superposed parts 202, 203becomes narrower in width than the lateral grooves 7, 8, as indicated byarrow R in FIGS. 35, 36. However, since the lateral grooves 7, 8 areoffset more towards the top plate section 1a than the mid position ofthe lateral member, the superposed portions 202, 203 are not positionedover the lateral grooves 7, 8, so that the superposed portions 202, 203are fused together reliably.

It is noted that the sheet-shaped member employed in the packagingmethod according to the present invention may also be a label member 205adapted to cover only the front side of the casing 100, as shown in FIG.42, instead of covering both the top plate section 1a and the bottomplate section 2a, as described in the foregoing. The label member 205has two parallel folding lines and is bent into U-shape. The foldedportion is offset towards one lateral side from the center of the labelmember 205 and both the flaps are spaced apart from each other by adistance corresponding to the thickness of the casing 100. The casing100 presents a planar outer surface when it is sheathed by the labelmember 205.

Various modifications of the casing for the disc cartridge according tothe present invention are hereinafter explained. Those parts orcomponents similar to those of the casing 100 shown in FIG. 4 areindicated by the same reference numerals and the correspondingdescription is omitted for simplicity.

A first modification of the casing for the disc cartridge according tothe present invention is first explained. The locking members 9, 10 aremounted on a pair of locking member mounting sections 33, 34 formed onthe bottom plate member 2. These locking member mounting sections 33, 34are formed on the rear parts of the opposing inner lateral sides of theouter sidewall members 17, 18, as shown in FIG. 16. These locking membermounting sections 33, 34 are provided with front and rear holdingprotrusions 54, 55, as shown in FIGS. 43 and 44. These holdingprotrusions 54, 55 are formed at the lower parts of the outer sidewallmembers 17, 18 for being protruded inwards in continuation to the bottomwall section 2a. That is, these holding projections 54, 55 are providedat the corners between the outer sidewall sections 17, 18 and the bottomplate section 2a. These holding protrusions 54, 55 are mounted facingeach other at a distance substantially corresponding to the lengths ofthe locking members 9, 10. The facing sides of the holding protrusions54, 55 are formed with holding recesses 52, 53, respectively. Theseholding recesses 52, 53 each have a substantially cylindrical innersurface and are opened towards the top with a cross-sectional profile ofa part of an ellipse or an oblong circle having its longer axis orientedin the fore-and-aft direction. The difference between the longer axisand the shorter axis of an ellipse of the cross-sectional profile ofeach of the holding recesses 52, 52 is on the order of e.g. 0.3 mm, ifthe grips 44, 45 are of a diameter on the order of 1.2 min.

The locking members 9, 10 are held by the holding projections 54, 55 byhaving the end grips 44, 45 fitted into the holding recesses 52, 53.These locking members 9, 10 are positioned with the axes of the grips44, 45 at right angles to the bottom plate section 2a and with theretention surfaces 47 directed towards the bottom plate section 2a. Thatis, the arcuately bent arms 46 of these locking members 9, 10 areadapted for being extended towards the inner side of the bottom platesection 2a.

As shown in FIG. 46, these locking members 9, 10 are designed for beingresiliently deflected in a direction of approaching the outer sidewallmembers 17, 18 as indicated by arrow C in FIG. 46. When the bent arms 46are deflected resiliently in this manner, the end grips 44, 45 are movedin the fore-and-aft direction within the holding recesses 52, 53. Anabutment boss 58 is provided on the opposite side of the retentionsurface 47 of each of the locking members 9, 10. When the arm 46 isresiliently deflected in a direction towards the outer sidewall members17, 18, the abutment boss 58 is abutted against the apex of an abutmentrib 57 provided at a mid part of each of the locking member mountingsections 33, 34, for preventing excessive resilient deflection of thearm 46 as shown in FIG. 46. The rib 57 is formed for extendingvertically between holding protrusions 54, 55 on the inner surface ofeach of the outer sidewall members 17, 18.

The inner sidewall members 11, 12 of the top plate member 1 are cut outat the rear ends so that the sidewall members 11, 12 extend from the topplate section 1a, at the cut-out parts, a shorter distance than at themid and front parts so as to leave avoid equal to the width of each ofthe locking members 9, 10. That is, the inner sidewall members 11, 12clear the locking members 9, 10 held by the locking member holding parts33, 34 while preventing these locking members 9, 10 from being detachedupwards from the locking member holding parts 33, 34.

The retention members in the casing 100 for the disc cartridge accordingto the present invention may also be locking members 9, 10 shown in FIG.44 in which the mid part of the bent arm 46 is flattened at 56, in placeof the locking members 9, 10 shown in the preceding embodiment. Thissecond modification of the casing for the disc cartridge according tothe present invention is hereinafter explained.

The mid parts of these locking members 9, 10 are designed as retentionmeans for being engaged in recesses 110, 109. When the disc cartridge101 is introduced into the casing 100, the locking members 9, 10 arethrust by front lateral surfaces of the cartridge main body 102 forresiliently deflecting the bent arms 46. When the cartridge main body102 is inserted up to a predetermined position inside the casing 100,the bent arms 46 are restored to their initial states for engaging theretention means in the recesses 110, 109. The locking members 9, 10,having the retention parts engaged in the recesses 109, 110, prevent thedisc cartridge 101 from being disengaged from the casing 100 under sockor vibrations.

Since the retention parts of the locking members 9, 10 have flattenedsurfaces, these flattened surfaces 56 are slid against the cartridgemain body 102 when the disc cartridge 101 is introduced into the casing100 to assure smooth and easy insertion of the disc cartridge into thecasing 100.

The retention members of the casing 100 may also be designed as lockingparts 60 formed as one with the bottom plate member 2, instead of thelocking members 9, 10 formed distinctly from the bottom plate member 2shown in the preceding embodiments. This third modification of thecasing for the disc cartridge is hereinafter explained.

These locking parts 60 are paired and formed at the inner rear surfacesof the outer sidewall members 17, 18 for facing each other. The lockingparts 60 are formed at the lower portions of outer sidewall members 17,18 as substantially plate-shaped members extended in the fore-and-aftdirection. These locking parts 60, 60 have their front sides formed asone with the outer sidewall members 17, 18, with their rear ends beingfree ends. The locking parts 60 may be resiliently deflected in adirection towards the outer sidewall members 17 ,18, with the front endsas fulcrum points, as indicated by arrow D in FIG. 48. The innersurfaces of the outer sidewall members 17, 18 are formed with clearances61 in register with the locking parts 60 to permit resilient deflectionof these locking parts 60.

The mid portions of these locking parts 60 are bent in a substantiallytrapezoidal shape directed towards the inside of the bottom platesection 2a. The mid portions of the locking parts 60 are formed asretention means engaged in the recesses 110, 109. When the disccartridge 100 is introduced into the casing 100, the locking parts 60,60 are resiliently deflected by being thrust by both front lateral sidesof the cartridge main body 102. When the cartridge main body 102 isintroduced up to a predetermined position within the casing 100, thelocking parts 60 are restored to their original states to permit theretention means to be engaged in the recesses 110, 109. The lockingparts 60, 60, having their retention means engaged in the recesses 110,109, prevent the disc cartridge 101 from being disengaged from thecasing 100 under shock or vibrations.

The retention means of the locking part 60 has a front inclined surface62 facing the inserting direction of the disc cartridge 101, shown byarrow C in FIG. 48. The front inclined surface 62 is sloped at a moremoderate tilt than the opposite rear inclined surface in order to permitthe locking parts 60 to be resiliently deflected more readily whenintroducing or taking out the disc cartridge 101 into or from the casing100.

A fourth modification of the casing for the disc cartridge according tothe present invention is hereinafter explained.

At the side of the locking member 9 in the interior of the casing 100,defined between the plate members 1 and 2, there is formed a lockingboss 70, which is to be a retention boss, as shown in FIGS. 49 and 50.The locking boss 70 is formed as one with the bottom plate member 2. Thelocking boss 70 is provided at a rear portion of the outer sidewallmember 18. The locking boss 70 is substantially semicylindrical-shapedand has its planar end face extending substantially parallel to thebottom plate section 2a and its semi-arcuate portion extending inwardsfrom the lateral surface of the outer sidewall member 18. The innersidewall members 11, 12 of the top plate member 1 are cut out at therear ends so that the sidewall members 11, 12 extend from the top platesection 1a, at the cut-out parts, a shorter distance than at the mid andfront parts so as to leave a void equal to the width of the lockingmember 9 and a void equal to the height of the looking boss 70, as shownin FIG. 53. That is, the inner sidewall members 11, 12 clear the lockingmember 9 held by the locking member holding section 33 and the lockingboss 70 while preventing the locking member 9 from being detachedupwards from the locking member holding section 33.

For accommodating and holding the disc cartridge 101 by the casing 100according to the above-described fourth embodiment, the disc cartridge101 is introduced via the opening in the casing 100 from the front side,as shown by arrow A in FIG. 4, into a space between the top platesection 1a and the bottom plate section 2a.

When the forward part of the disc cartridge 101 reaches the rear end ofthe casing 100, the forward end of the lateral surface of the cartridgemain body 102 facing the locking member 9 thrusts the retention surface47 of the locking member 9 for deflecting the arm 46 towards the outersidewall member 17. At this time, the forward end of the oppositelateral surface of the cartridge main body 102 is caused to bear againstthe peripheral surface of the locking boss 70 so as to be shiftedslightly towards the locking member 9. When the forward edge of thecartridge main body 102 is inserted up to a predetermined position inwhich it is substantially abutted against the inner sidewall section 15of the casing 100, the locking member 9 and the locking boss 70 face therecesses 109, 110, respectively. The arm 46 of the locking member 9 isrestored at this time to its initial state under its own resiliency,with the retention surface 47 being intruded into recess 109, as shownin FIG. 52. The locking member 9 thrusts the cartridge main body 102towards the opposite side for introducing the locking boss 70 into theopposite side recess 110.

The distance between the apex of the retention surface 47 and that ofthe peripheral surface of the locking boss 70, indicated by arrow L_(c)in FIG. 52, is selected to be smaller than the width of the cartridgemain body 102, shown by arrow W in FIG. 52. Consequently, with theretention surface 47 of the locking member 9 and the locking boss 70introduced into the recesses 109, 110, the cartridge main body 102 isretained by being clamped from both lateral sides and thereby preventedfrom being disengaged via the opening of the casing 100 towards theoutside under shock or vibrations.

The mistaken insertion inhibiting protrusion 29 is engaged at this timein the disc type discriminating recess 111 of the disc cartridge 101.

The disc cartridge 101, thus accommodated in position within the casing100, is contained between and protected by the plate members 1 and 2.For taking out the disc cartridge 101 out of the casing 100, the rearparts of the disc cartridge exposed to outside via cut-outs 5, 6 arepulled rearwards with respect to the casing 100. The locking member 9then has its retention surface 47 thrust by the front part of thelateral surface of the cartridge main body 102 so that the arm 46 isflexed towards the outer sidewall member 17 to release retention of thecartridge main body 102. At this time, the disc cartridge 101 may betaken out of the casing 100 via the opening. If the disc cartridge 101is moved further rearwards, the locking member 9 is reset to its initialstate. The disc cartridge 101 may be taken out of the casing 100 bypulling the disc cartridge outwards.

The casing 100 for the disc cartridge according to the present inventionmay also be provided with a pair of locking bosses 71, 71, as retentionbosses, on both inner lateral surfaces of the main casing member, inplace of the locking member 9 and the locking boss 70. These lockingbosses 71, 71 are formed at rear parts of the outer sidewall members 17,18 in opposition to each other. The locking bosses are formed as onewith the outer sidewall members and with the bottom plate section 2a.These locking bosses 71, 71 are substantially semicylindrical-shaped andhave their flat end faces parallel to the outer sidewall members 17, 18while having the semi-arcuate peripheral surfaces extending upwards fromthe bottom plate section 2a, as shown in FIG. 57.

The present casing 100 is not provided with the flange 22 providing therear engaging rib 16 and the rear engaging groove, with the outerlateral surface of the inner rear wall member 15 and the innerperipheral surface of the outer rear wall member 19 being planar, asshown in FIG.53 and 54. That is, with the lateral sidewall sections ofthe top plate member 1 and the bottom plate member 2 in engagement witheach other, the rear wall members 15, 19 are caused to bear against eachother and yet are movable vertically relative to each other.

With the present casing 100, the sidewall sections 11, 12, 17, 18 areengaged at an area L₁ except a rear part L₂ as shown in FIG. 56. Thatis, with the present casing 100 for the disc cartridge, the rear partsof the top plate member and the bottom plate member are resilientlyflexed in a direction away from each other. The rear wall members 15, 19may also be engaged with each other at a central area L₄ excluding bothlateral side areas L₃ in FIG. 56, in which case both lateral side areasof the top and bottom plate members may be resiliently flexed at therear end portions in a direction away from each other.

When the disc cartridge 101 is introduced into the casing 100 such thatthe forward end of the disc cartridge 101 reaches the rear end of thecasing 100, both front lateral sides of the bottom plate section of thecartridge main body 102 thrust the upper surface of the locking bosses71, 71 for deflecting the bottom plate section 2a downwards, that isaway from the top plate section 1a. At this time, the rear parts of thelateral grooves 7, 8 are widened from the initial state, as indicated byarrow C in FIG. 59. When the forward end of the cartridge main body 102is introduced up to a predetermined position in which it issubstantially abutted against the inner rear wail member 15 of thecasing 100, the bottom plate section 2a is faced by the recesses 109,110. The bottom plate section 2a is restored at this time under its ownresiliency, as shown in FIG. 60, with the locking bosses 71, 71 beingengaged in the recesses 109, 110.

The distance between end faces of the locking bosses 71, 71 indicated byarrow L_(c) in FIG. 59, is selected to be smaller than the width of thecartridge main body 102 indicated by arrow W in FIG. 52. Consequently,by having the locking bosses 71 , 71 introduced into the recesses 109,110, the cartridge main body 102 is retained by being clamped from bothlateral sides and thereby prevented from being disengaged via theopening of the casing 100 towards the outside under shock or vibrations.

The disc cartridge 101, thus accommodated in position within the casing100, is contained between and protected by the plate members 1 and 2.

For taking out the disc cartridge 101 out of the casing 100, the rearparts of the disc cartridge exposed to the outside via cut-outs 5, 6 arepulled rearwards with respect to the casing 100. The locking bosses 71,71 thrust by the front part of the lateral surfaces of the cartridgemain body 102 so that the rear part of the bottom plate section 2a isdeflected in a direction away from the top plate section 1a to releaseretention of the cartridge main body 102 by the locking bosses 71, 71.At this time, the disc cartridge 101 may be taken out of the casing 100via the opening. If the disc cartridge 101 is moved further rearwards,the rear part of the bottom plate section 2a is returned to its initialstate as compared with the top plate section 1a. The disc cartridge 101may be taken out of the casing 100 by pulling the disc cartridgeoutwards.

If, with the present casing 100, a pair of locking bosses are formed atboth inner lateral sides of the main casing member, these locking bossesmay be substantially triangular-shaped with the triangular end facesextending parallel to the outer sidewall members 17, 18 and with upperridges defined by inclined surfaces being protruded upwards away fromthe bottom plate section 2a.

A fifth modification of the casing for the disc cartridge according tothe present invention is hereinafter explained.

In the rear outer lateral surfaces of the inner sidewall members 11, 12of the top plate member 1 are formed a pair of recesses 80, 81 definingbottomed holes. These recesses 80, 81 are formed as grooves extendedvertically from the proximal sides up to the lower ends of the innersidewall members 11, 12, that is from the lower surface of the top platesection 1a up to the vicinity of the lower ends of the inner sidewallmembers 11, 12, as shown in FIG. 61.

In the rear parts of the outer sidewall members 17, 18 of the bottomplate member 2 are formed a pair of slits 82, 83 for defining a bottomedhole in register with the recesses 80, 81. These slits 82, 83 are formedin a direction from the upper ends towards the proximal ends of theouter sidewall members 17, 18, as shown in FIG. 63.

On the other hand, recesses 37, 38 formed on the upper ends of the outerlateral surfaces of the outer sidewall members 17, 18 and the vicinityof the lateral sides of the top plate section 1a define theabove-mentioned lateral grooves 7, 8. That is, the upper sides of theouter sidewall members 17, 18 are caused to bear against the lateralsides of the top plate section 1a at positions offset inwards by adistance equal to the depth of the recesses 37, 38 as shown in FIG. 20.These lateral grooves 7, 8 are formed for extending from the front sidesup to the rear ends of the lateral surfaces of the casing 100.

Into these lateral grooves 7, 8 are inserted supporting pieces of arack, not shown, adapted for housing and supporting a plurality of thecasings 100. That is, the above-described casing 100 is supported by therack by means of the supporting pieces by having the supporting piecesintroduced into the lateral grooves 7, 8.

On the rear side of the bottom portions of these lateral grooves 7, 8are formed the bottomed holes which are defined by the slits 82, 83 inthe outer sidewall members 17, 18 being superposed on the recesses 80,81 in the inner sidewall members 11, 12.

These bottomed holes play the role of retaining the casing 100 by havingengaging members of the rack engaged therein. These bottomed holes areof a depth sufficient to permit the engaging members to be engagedtherein. The depth of the bottomed holes, indicated by arrow G in FIG.63, corresponds to the depth of the recesses 80, 81 and the thickness ofthe outer sidewall members 17, 18 summed together, as shown in FIG. 63.Such depth is deeper than the thickness of the outer sidewall members17, 18 or the thickness of the inner sidewall members 11, 12.

A sixth embodiment of the casing for the disc cartridge according to thepresent invention is hereinafter explained. In the present modification,the lateral grooves 7, 8 are not limited to those defined by the topplate 1a and the recesses 37, 38, as in the preceding embodiment, butmay be defined by the upper end faces of the outer sidewall members 17,18, outer lateral surfaces of the inner sidewall members 11, 12 and bythe vicinity of the ends of the top plate section 1a, in which case theinner sidewall members 11, 12 have the lower ends abutted against thebottom plate section 2a and are provided on their outer sides withstep-shaped abutments 85, as shown in FIG. 64. The outer sidewallmembers 17, 18 are free of the recesses 37, 38 but are formed as planarupper end faces. The outer sidewall members 17, 18 have the upperlateral end portions abutted against the lower surfaces of the abutments85, while being abutted against the outer lateral surfaces of the innerside wall members 11, 12 by their inner lateral surfaces.

If the lateral grooves 7, 8 are defined by the upper end surfaces of theouter sidewall members 17, 18, the outer lateral surfaces of the innersidewall members 11, 12 and the vicinity of the ends of the top platesection 1a, the inner sidewall members 11, 12 may also be free of theabutments 85, as shown in FIG. 65. In such case, the outer sidewallmembers 17, 18 are caused to bear and support the lower end portions ofthe outer lateral surfaces of the inner sidewall members 11, 12.

The lateral grooves 7, 8 may also be defined by the recesses 37, 38formed on the upper ends of the outer sidewall members 17, 18, the outerlateral surfaces of the inner sidewall members 11, 12 and the vicinityof the end parts of the top plate section 1a, as shown in FIG. 66. Insuch case, the inner sidewall sections 11, 12 have their ends abuttedagainst the bottom plate section 2a and are provided on their outersides with step-shaped abutments 86. The outer sidewall members 17, 18are formed with the recesses 37, 38. These outer sidewall members 17, 18have their upper ends, that is the portions thereof offset more inwardlythan the recesses 37, 38, abutted against the lower surfaces of theabutments 86. Besides, the outer sidewall members are abutted againstand support the outer lateral surfaces of the inner sidewall sections11, 12 by their inner lateral surfaces.

Besides, since the recesses making up the lateral grooves 7, 8 are freeof upwardly projecting parts, such as flanges, molding may be achievedby a metal mold of a simplified structure which is made up only of anupper mold 501 and a lower mold 502 and which is not provided with aslide core, as shown in FIG. 67.

With the present modification, high mechanical strength of the casingfor the disc cartridge may be achieved since the lower ends of the innersidewall members 11, 12 are abutted against the bottom plate section 2a,the upper ends of the outer sidewall members 17, 18 are caused to bearagainst the top plate section 1a and the outer sidewall members 17, 18are caused to bear and support the outer lateral surfaces of the innersidewall members 11, 12.

What is claim is:
 1. A casing for a disc cartridge having a pair ofrecess portions which are formed on each lateral side thereof, the casecomprising:a first half having a square-shaped plate portion, a pair ofsidewall sections formed along parallel sides of said plate portion anda rear wall formed between said sidewall sections of the first half,each sidewall section having a projection formed along an outsidesurface of the sidewall, the pair of sidewall sections and the rear wallsections combining to form a first U-shaped peripheral section; a firstengaging member formed on the outside surface of a first sidewallsection of the first half; a second engaging member formed on theoutside surface of a second sidewall section of the first half; a thirdengaging member formed on an outside surface of the rear wall of thefirst half; a second half having a square-shaped plate portion, a pairof sidewall sections formed along parallel sides of said plate portionof said second half and a rear wall formed between said sidewallsections of said second half, each sidewall section of the second halfhaving a projection formed along an inside surface of the sidewall, theprojection of the second half having a recess, the rear wall of thesecond half having a recess, the pair of sidewall sections and the rearwall combining to form a second U-shaped peripheral section; and a pairof holding members formed as a curved-shaped member for engaging a pairof recess portions in a disc cartridge when the disc cartridge iscompletely inserted into said casing, the pair of holding membersconnectable to the sidewall sections of the second half so that eachsidewall section is connectable to one holding member, each holdingmember being positioned adjacent to an intersection of the rear wall andthe sidewall section of the second half, wherein when the first half isinserted into the second half, the projections of the first half engagethe projections of the second half, and the engaging members of thefirst half engage the recesses of the second half.
 2. The casing asclaimed in claim 1 wherein the first engaging member is positionedbetween the projection formed on the outside surface of the firstsidewall section and the plate portion of the first half, and whereinthe second engaging member is positioned between the projection formedon the outside surface of the second sidewall section and the plateportion of the first half.
 3. The casing as claimed in claim 2whereinthe recess portions have a depth less than the distance betweenthe plate portion of the second half and the projection of the secondhalf.
 4. The casing as claimed in claim 1wherein when the first half andthe second half are connected together to form the casing, the casinghas lateral walls and a pair of grooves on outer portions of the lateralwalls.
 5. The casing as claimed in claim 1 wherein said second halffurther comprises mistaken insertion inhibiting means connected to thesecond half for preventing a disc from being inserted into the casingincorrectly.
 6. The casing as claimed in claim 5 wherein the mistakeninsertion inhibiting means is provided adjacent to a corner which isformed by said rear wall section of the second half and said plateportion of said second half.
 7. A casing for a disc cartridgecomprising:a first half having a square-shaped plate portion, a pair ofsidewall sections formed parallel to said sides of said square-shapedplate portion and formed more inwardly than the edges of saidsquare-shaped plate portion, and a rear wall section offset moreinwardly than the edge of said plate portion for interconnecting saidsidewall sections, said sidewall sections each having a projectionformed along an outside surface of the sidewall, a first engaging memberformed on the outside surface of a first sidewall section of the firsthalf; a second engaging member formed on the outside surface of a secondsidewall section of the first half; a third engaging member formed on anoutside surface of the rear wall of the first half; a second half havinga square-shaped plate portion and a pair of sidewall sections upstandingfrom parallel sides of said plate portion and a rear wall sectionupstanding from said square-shaped plate portion of said second half forinterconnecting the sidewall sections, each sidewall section of thesecond half having a projection formed along an inside surface of thesidewall, the projection of the second half having a recess, the rearwall of the second half having a recess, and a pair of holding membersfor holding said disc cartridge in position within said casing, the pairof holding members formed as a curve-shaped member for engaging a pairof recess portions in a disc cartridge when the disc cartridge iscompletely inserted into said casing, the pair of holding membersconnectable to the sidewall sections of the second half so that eachsidewall section is connectable to one holding member.
 8. The casing asclaimed in claim 7 wherein when the first half and the second half areconnected together to form the casing, the casing has lateral walls anda pair of grooves formed on the outer portions of said lateral walls. 9.The casing as claimed in claim 7 wherein at least one holding member isprovided adjacent to a corner which is formed by said rear wall sectionof the second half and said plate portion of said second half.
 10. Acasing for a disc cartridge comprising:a first half having asquare-shaped plate portion, a pair of sidewall sections formed alongparallel sides of said plate portion and a rear wall formed between saidsidewall sections, a second half having a square-shaped plate portion, apair of sidewall sections formed along parallel sides of said plateportion of said second half, a rear wall formed between said sidewallsections of said second half, and a rear step formed on the second halfadjacent to the rear wall, engaging means for connecting the first halfto the second half, holding means formed on said second half for holdingsaid disc cartridge in position within said casing, and a mistakeninsertion inhibiting protrusion provided on said rear step.
 11. Thecasing according to claim 10 further comprising locking means formed onthe sidewall sections of the second half near the rear wall.
 12. Thecasing according to claim 11, wherein the locking means is formed as anintegral portion of the second half.
 13. The casing as claimed in claim10 wherein when the first half and the second half are connectedtogether to form the casing, the casing has lateral walls and a pair ofgrooves formed on the outer portions of said lateral walls.
 14. Thecasing as claimed in claim 1, wherein the sidewall sections of the firsthalf each have a recess portion that defines a contact edge, and whereinthe contact edge rests upon one holding member.